Superposed telegraph system and bridge duplex set for use with such systems



Jan. 6, 1931. RQ V. MoRGENsTi-:RN

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Il Il Il R. V. MORGENSTERN SUPERPOSED TELEGRAPH SYSTEM AND BRIDGE DUPLEX SET FOR USE WITH SUCH SYSTEMS Filed Sept. 4, 1929 2 Sheets-Sheet 2 Patented Jan. 6, 1931 unir-eo sursis `.e.er-snr ortica YORK EONALn-v. Mone-ENSTERN, OE METnCiIEN, NEW JERSEY, AssIGNonTO THEWESTERN UNION TELEGEAPH COMPANY, OE NEW YORK, N.`Y.,1A CORPORATION OE NEW s'cPEErosED TELEGEAPH SYSTEM AND BRIDGE .DAUPLEXSET .EOE USE jwiTII SUCH SYSTEMS Application filed September y movement of the distant transmitting device,

but will be unaiiected by the operation of the transmitting device located at its homeset.

A further Obj ect of the invention is to pro- ,vide a bridge `duplex set so designed that .it may form part ot a Superposed metallic telegraph system, and so associated with the system that there shall be no interference between the superposed circuitv and the circuit on which it is superposed.

More Specifically, the objects of the inven- Y tion are to provid-e a novel bridge duplex set by means ot a bridge consisting of our'coils wound on a common magnetic core.

The purpose of the four coil bridge is to provide conjugate terminals forthc transinitter and receiver ofthe terminal set of which it 'forms a part.

A further object ot the tour-coil bridge isl to provide a non-inductive path 'for currents from the transmitter'of the terminal set of which it forms a part, and alsoywien the bridge forms a part ot a metallic circuit set of a superposed system, to provide a noninductive path for currents of the superposed circuit.

A still further ob]- ect oi the four-'coil bridge in a superposed system is to provide points at the terminals ot the metallic circuit rclay which are equipotential with respect to currents 'trein the superposcd circuit.

related objectis to oli'er ahiglxly indue 'tivo nath to currents trom the trr-insmitterot a distant, corresponding terminal set. in order to selectively direct the received-currents to the windings ot the receiving relay of the set. l Y

'.l`he invention is explained. in connection with a simple metallic telegraph circuit, vand also in connection with a superposed system. The metallic circuit stations at opposite ends oi the metallic line conductors are ret-erred to as comprising sets A. and B, and sets A1 4, 1929. `semi No. 396,341.-

and B1, while the superposed circuit' stations at opposite ends of'tliesystcrn comprise sets C and CH itis to be understood that the bridge duplex set of this invention may be used at any or all of these stations. also tofbe understood that, though specially adapted for use-with superposed vmetallic telegraph systems, the invention may also be used as an individual terminal telegraph set.

Gbviously, theprinciples Ot the invention may be applied 4also to any typeot metallic. Vsystem 1n which it'may be desired to provide.

duplex operation,ancwparticularly to systems of the superposed type in: which inter- 'ference must be v`1prei/"ented' between the metallic circnitsand the superposed circuit.

In the-circuits illustrated'` the receiving apparatus. for the metalliccircuits and forthe superposedcircuit.comprises a polarized rclay having. v*two mainfwindings preferably although not necessarily designed to lit. the windings oi the bridge. The two coils ot the relay maybe coni'iected in either ot two ways,- as shown in F laand 17). For reasons which will appear hereinafter, the ar "ange ment of Fig. 1b is preferred. Y

Figs. la and lb may be treated assiinple metallic telegraph circuits, or else als portions ot superposed systemsl of the'type shown' in 2. i The invention will be understood by reference to the following description rand the accompanying drawings in which:

Fig. la; and Figllb show the invention applied to metallic telegraph circuits. lnboth figures the relay windings are connected in opposite directions to corresponding points on the bridge. l v

` In la onewinding of the receiving relay is connected acrossthe terminals of the bridge coils which areconnected to line7 and vthe other across 'the terminals of the bridge It isa terminal of the artificial line 20; to theend terminals 3 and 4 of theother pair arecon` nected the-other line conductor and the otherl terminalof the artilicial line. The common terminals 5 and 6 of the pairs are connected` to the transmitting device 7 y., In the present case, the transmitting device is represented conventionally by the tongue and contacts of a transmitter, thecontactsbeing connected through current limiting resistances to sources of potential 19. i The common point of these sources is'v connected to terminal 5 and the tongue of the transmitter to terminal 6.

The winding 8 of the twoswinding receiv ing relay of set A is connected to terminals 1 and 3 of the bridge,and the winding 9 to terminals 2 and 4; that is, winding 8 is connected across the terminals'of thebridge coils which are connected to line, vwhile winding 9 is connected across the terminals of the bridge coils which are connected to the artificial line.

Thepairs of coils of the bridge 10 and of all the other bridge elements shown) lare connected so that the'two windings in each pair will set upa iiuX in the core in the same direction when the two ends of the pair are connected to a source of current. This is the situation with respect to incoming currents from a corresponding distant station. lNo

flux wi-ll be set up when equal currents are passed in opposite directions through the two coils of the pair. This is the situationwhen current is applied from the transmitter of the home seti It is also the situation when current is transmitted or receivedV at the terminal set ot the superposed circuit b v way of the metallic circuit bridge, as will be eX- plained in connection with Fig. 2.

The artificial line illustrated is ot' the usual type, having one resistance and three capacity branches.` Inductance, although not shown, can be added, it necessary, but the exact design of the artificial line is immaterial to the practiceof my invention so long vas it provides proper balance for duplex operation.

- At station B, the line terminals are indicated at 21and 23, the artificial line terminals at` 22 and 24. The bridge is indicated generally by the numeral 30 and the bridge wind ings by 31, 32, 33`and 34. The common terminal 25` of coils 31 and 32, is connectedY to the tongue of the transmitting device 27, while shunt 51.

the'common terminal 26 is connected 'to theY common return of the metallic battery.

'The receiving relay of set B comprises two windings 28 vand 29, which are connected in tlie saine way as are the windings of the receiving relay of set A. That is, Winding 28 is connected across the line conductors at terminals 21 and 23, while winding 29 iis connected across the artificial line at terminals 22 and 24. It will be noted that relay windings 28 and 29 are connected in opposite directions to corresponding points on the bridge.

"In 1b, the same reference numerals are fused. vtof,indicate corresponding parts. The only dierence between Fig. 1a and Fig. 1?) is in themanner of connecting the windings of the receiving relay. in Fig. 17;, the winding 8 ot tlie receiving relay connected. trom line conductor terminal 3 to artilicial Vline terminal 4, and winding 9 is connected from line conductor vterminal 1 to artificial line conductor'terminal 2. Similarly, atv set B, the winding 28 of the receiving relay isl terminals 5 and G wliile the transmitting de- 'ice 27 of set B is connected to the terminals and 26.

in Fig. 2tl1econnection of tlie transmitting devices and receiving relays ot' theter'- min-al apparatus-ot the metallic circuits corresponds to that shown in Fig. 17). rhat is, in sets A, and A1 the transmittingI devices are connected across .the common terminals 5 and 6 and in sets Band B1 they are connected across terminals 25 and 2G. The windings 8. of the receiving-relays ot setsA and A1 are connected across the terminals v3 and 4 while the windings 9 of these relays arc connected across the terminals 1 and 2. in sets B and B1, the windings 28 of the receiving relays arcconnected across the terminays 23 and 24, Vwhile the windings 29 are connected acrossvthe terminals 21 and 22.

Fig. 2zshofws, in addition, means for su- .1;

No. 258,948, tiled March 3, 1928, entitled Supcrimposed telegraph circuits.

The superimposed circuit is conductii'cly coupled to the electrical center ot' the source 19 of metallic signaling current by means or Ya shunt 5l comprising inductive resist ance coils 52, 54 and resistances 53, 55 which may be variable. The conductor 50 of the superimposed circuit is connected to the electrical midpoint ot theV inductive resistance A similar conductor 8O leads to the electrical midpoint of an inductive reter-` la, the transmitting Vdevice i" ot Fie. 1b' of' set A is connected to common cuit are connected to the terminals 7l and 73 a bridge 8O comprising tour coils 8l, 82, 88 and 8st.

and 3 ot station A. An artificial line 100is connected to terminals 72, 7l-ot the bridge 8l). A receiving relayior the superimposedv circuit coi'nprises windings 88 and 89, 88 bcing connected betweenterminals 78 ,and 74E, While 89 is connected between terminals 7l and rthis arrangement oiz coil windings is the saine as that shown in Fig.l lb. The transmitting device 8? of the superimposed circuit terminal set is connected to the coinmon termina-ls 8g3 and 8G ot the bridge 80.

At the opposite end of the system, the distant`station comprisesa terminalset C for the super-posedA circnit Whose elements are similar to those ot the terminal set C.

In discussing the operation ofthe sets ot Fi la, it will be assumed t0 start that the two points at which battery is normally connected to the coils of the bridge of set B are linked together electrically Vby means of the resistance shown in dotted lines, instead of through the transmitting device and battery. It will then be possible to send signals in one direction only, namely from set A to set B, and the only current in the circuit l" will be that originating from setA. y l lf set A is to be operated duplex, it must not respond to the operation V'otits transmitting device which operates the receiving relay at set B.

It the artificial lineot setA is so adjusted that it has an impedance eqiial to the sending end impedance of the circuit beyond the line terminals ot the bridge at set A over the frequency range in which the duplex system operates, 1.roi-hing the transmitting device at set A will have no ette-ct on the receiving relay forming a part of set A. This is so because with the artiiicial line properly adjusted the voltage dropacross the points 1 and 2 is the saine as across 3 and el and points l and. 2 'will bear the saine relationship (i. c. positive or ncgatiyc) to points 3 and et. Hence equal currents will flow in opposite fliprections through thc two coils ottlic relay' and. there n'ill bc no magnetic 'flux tending to more the relay tongue.

rit set B the potential drop across points 2l and 23 will be greater than that across points 22 and 24 becausethere will be relatively little of the line current tloiv from point to 26 (or vice versa) through the path composed of the two bridge coils 8l and 3B in series With the artiticialline for the reason that the impedance of this path is high co1npared to that through the resistance shownin 'oken lines.

`With a proper adjustment of the artificial lino,- equal currents flow in opposite direc tions through each of the bridge coils ot a pair. Under these conditions no flux will be set up in the core and hence the inductance will be zero. The bridge `will then act as a non-inductive resistance only to outgoing signals.

llt now the resistance oit set B is replaced' by sources oi potential connected to the transf mitting device, and if set B is balanced, the receiving relay of Veach set Will respond to a movement ot the distant transmitting dcvice, but Will be unaffected by the operation ot the .transmitting device located at' its honie set.

Referring noiv to Fig. l?) When the artin icial line of a terminal set isproperly adjusted, the potential between points l and 2 and 3 and Il, due to the battery at the same set, is Zero, and hence the receiving relay Will not respond to outgoing signals. On signals originating at the distant set, there AWill vbe a difference' in potential between points 1 and 2 and 3 and e. It point l positivevvith respect to point 2, then point 3 Will be negative With respect to point e.

Therefore by connecting the relay coils as` shown', i. e. in opposite directions to corresponding points on the bridge, the tivo coils on the relay Will aid each other in causing the relay lto operate; l Y f The operation of the system'ot Fig. 2 is as follows:

As in the case of Fig. lb, signals originating at the transmitter 7 will not affect the receiving relay of the same set because the balanced condition ot the bridge prevents any voltage from being applied across terminals l and 2 or across terminals i3p and el. Therefore no current flows through either of the coils 8 and 9 of the receiving relay of the home set. At the samev time the coils ot the bridge l0 are so Wound that they offer a non-indnc tive path to the signals from transmitter T. The bridge 8O ot the terminal set C of the superposed circuit functions in the same Way with respect to signals from transmitter 8. That is, by reason ot the balanced condit n of the bridge. no current flows through the coils 88 and 8l) of the receiving relayol' .wot C. and, by reason oit thc direction of winding; oi the coils of bridge 80, it oli'crs a non-'indoctive path to currents from trai'ismitter 8T flowing to conductors 50 and 60, and then over the line conductors ot each metallic circuit in parallel. l

The superposed currents from the trant 1nitterf87 Which are applied to the niid points ot the inductive shunt 51 then pass to the line "conductors oi' a metallic circuit via thebridge coils connected in series with the line conductors. By reason of the direction of winding the bridge coils oder non-inductive paths to currents from the superposed circuit. By reason of the balanced condition ot the system, VtheV potential between points l and 2' caused by the presence of the superposed circuit is the same as that between points 3 and 4 from the same source. Furthermore points` 1 and 3 and points 2 ,and` 4 have the saniepotential relations with respect to each other' There will be therefore no tendency tor a relay on the circuit on which the superposing is done to respond to signals transmitted over the superposed circuit.

As disclosedl in the copending application referred to above, any tendency for current.

Y to flow from transmitter 7 throughtheshunt l is minimized because of the nature 'of the shunt.. f Y Y rlhus, the transmitter of set A causes no interference with the receiver of setA norY tere with each other, nor does set C1 interfere with set B1 or set B1, nor sets Band B1 with set C1. 1 Y

lt is obvious that if in Fig. 2 the manner ot connecting the relay windings ot Fig. liawere used instead ot that of Fig. 16, the saine general conditions would hold'good. .For each bridge it would hold true that there would be no `voltage drop from the superposed circuit across the points 1. and 8 because equal currents would-.flow through from points 5 and 6 to points l and 3. Hence there would be no voltage across l and 3 tending to cause the relay of set A to operate.

Since there is no tendency Jfor the current 1from the superposed circuit to liow from points 5 and 6 te 2 and 4, there will be no potential across the other relay coil.

l claim:

l. A bridge duplex telegraph set comprising a common closed core of magnetic material, a plurality of pairs of windings on said core arranged to provide a common terminal and end terminals for each pair, transmitting means connected to common terminals of the pairs, and receiving means connected to the end terminals ot the pairs.

2, A bridge duplex telegraph set comprising a common core ot magnetic material, a pulrality of pairs windings on said core couiiected to provide a common terminal and cud terminals for each pair,`line conductors connected to correspondingend terminals ofthe pairs. a balancingartificial line conl nected to the other end terminals ot the pairs,

relay connected to the end terminals or" th i` pairs. Y

3. A b 'idge duplex telegraph set comprisplurality ot pairsof windings on said core connected to provide a common terminal and end terminals for each pair, line conductors connected to corresponding end terminals of the. pairs, aV balancing artificial line connected to the other end terminals of the pairs, a transmitter connected to the common terminals of the pairs and a two-coil receiving relay having one coil connected to the two end terminals of a pair and a second coil connected to the two end terminalsot the other pair.

4. A duplex bridge telegraph set adapted for connection as a terminal set for a telegraph line comprising anA inductance coil having two pairs of windings `and a closed core, the windings being arranged to provide six terminals of which two are common terminals of said pairs, and means for including vthe line conductors across two ot the tour individual terminals and an artificial line acrossA the other two individual terminals. Y

5. A duplex bridge telegraph set comprising a. transmitter, a receiver and a tour-coil bridge with means for connecting twol coils together and to one terminal ofthe transmitter, meansffor connecting the other two coils together and to the other terminal of the transmitter, and means for connecting the receiver to all four'arms of the bridge.

6. A superposed telegraph system comprising a metallic circuit and means. comprising inductances for superposing a circuit thereon, transmitting apparatus for said superposedcircuit, and transmitting apparatus for said metallic circuit, said means providing a non-inductive path to currents from each of said transmitting apparatus.

7. A superposed telegraph system coinprising a pairot metallic line conductors and a tour coil bridge, an artilicial line, transmitting means for the metallic circuit, transmitting means :tor the superposed circuit, means to connect the artilicial line to terminals of two of said coils and the metallic line conductors to terminals of the other two coils, and means to connect both transmitting means at the other terminals of said coils.

8. The combination according to claim 7 and receiving apparatus for the metallic circuit comprising relay coils connected to the line and articial line terminals ot said coils;

9. A superposed telegraph system comprising a pair of metallic line conductors and a tour coil bridge, an artificial line connected to terminals of two coils of said bridge so as to provide duplex operation over the metallic circuit, and means for superposing a circuit on said line conductors by way of said fourcoil bridge.

10. A superposed telegraph system comprising two. pairs ofmetallic line conductors,

means for providing duplex operation over each pair of metallic conductors, each of said means comprising a four-coil bridge andV means for superposing a telegraph circuit on said pairs of metallic conductors by way ofv said four-coil bridges.

11. A superposed telegraph system comprising a pair of line conductors forming a metalliccircuit, a four-coil bridge, an artiiicial line and a pair of artificial line conductors leading thereto, a source of transmitting current for said superposed circuit and means for connecting the source to each of the line conductors and artificial line conductors by way of one coil of said bridge, and a receiving relay for the metallic circuit connected between equipotential points on saidlineand artificial line conductors.

12. A superposed telegraph system coni` prising a pair of line conductors forminga metallic circuit, a four-coil bridge, an artificialline and a pair of artiiicial line conduc tors leading thereto, a source of transmitting current for said superposed circuit and means for connecting the source to each of the line conductors and artiiicial line conductors by way of one coil of said bridge, and a receiv ing relay for the metallic circuit comprising two windings each of which is connected across equipotential points on said conductors;

13. A superposed telegraph system comprising a pair of line conductors forming a metallic circuit, a four-coil bridge, an artificial line and a pair of artificial line conductors leading thereto, a source of transmitting A current for said superposed circuit and means for connecting the source to each of the line conductors and artificial line conductors by D way of one coil of said bridge, and a receiving relay for the metallic circuit comprising two windings each of which is connected between equipotential points on aline Vconductor andan artificial line conductor.,v

14. A telegraph circuit comprising a pair lof line conductors and an artificial line, a terminal set comprising a transmitter and a receiver having two relay windings, an -in-` 1" ductance device comprising a plurality .of

windings on a common core, and'means for connecting said device to Vthe linel and artificial line so as to provide terminals for said transmitter and two sets of terminals for the relay windings both of which shall be conjugaile with respect to said transmitter termina s.

In testimony whereof I aiiix myisignature.

RONALD V. MORGEN STERN. 

